Find联合查询

class Project < ActiveRecord::Base
  has_many :tasks
end

class Task < ActiveRecord:Base
  belongs_to :project
end

## 查找某一个项目下的未完成任务, 按时间逆序排序
@project = Project.find(param[:id])
@task = @project.tasks.find_by_complete(false, order: "created_at DESC")

于2015-03-20